Field of the Invention
The present invention relates to a radio communication system employing digital audio communication, a radio apparatus used in the system, and a radio communication method, a packet data generation method, and a method for reproducing data from a packet, that correspond to the system.
Description of the Related Art
In recent years, a digitized and networked environment for audio communication has been developing in the field of amateur radio for example, so that the users can enjoy communication at a higher speed and exchange clearer audio messages. In a radio communication system employing such digital audio communication, audio signals are encoded and converted into digital signals, and are transmitted after being packetized (for example, see JP 2006-157477A).
In the aforementioned radio communication system, data indicating a call sign of the transmission destination, data indicating a call sign of the transmission source, etc. are added to the header part of the packet, and accordingly the system can achieve many functions such as the function of performing communication with the designation of the communication party radio station, which cannot be achieved by analogue radio communication systems.
Furthermore, according to the aforementioned radio communication system, audio frames and data frames, each having a predetermined length, are consecutively arranged one after the other, so that data for audio communication and data for data communication can be simultaneously transmitted.
Therefore, with use of this function, image signals captured by a camera can be transmitted from one radio apparatus to another radio apparatus during communication, and the image is displayed on a display and the users can enjoy a conversation while viewing the image, for example.
Meanwhile, since the aforementioned radio communication system is designed for audio communication, the amount of data that can be transmitted in data communication is set to be smaller than the amount of data that can be transmitted by audio communication, and accordingly the communication speed of the data communication is not necessarily high.
Therefore, only some of the image signals can be transmitted during a single call, and users cannot enjoy a conversation while viewing the image. For this reason, improvements have been demanded by users.